<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      div {
        width: 500px;
        height: 500px;
        margin: 50px auto;
        /*background: url(images/ufo.png)no-repeat 50% 100%,url(images/stars.png) no-repeat 0 0,url(images/sky.png) no-repeat 0 0;*/
        background-image: url(images/ufo.png), url(images/stars.png),
          url(images/sky.png);
        background-position: center bottom, 0 0, 0 0;
        background-repeat: no-repeat, no-repeat, no-repeat;
      }
    </style>
  </head>
  <body>
    <div></div>
  </body>
</html>
